Conventionally, in X-ray diagnosis apparatuses and X-ray Computed Tomography (CT) apparatuses, an X-ray high voltage generator is used for the purpose of supplying high voltage to an X-ray tube. The X-ray high voltage generator is, generally speaking, a high voltage power supply in which an inverter circuit, a high voltage transformer, a rectifying circuit, and the like are combined together.
Examples of a switching device provided for the inverter circuit include, generally speaking, a power device (a power element) such as an Insulated Gate Bipolar Transistor (IGBT) or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS-FET). Because a large current flows through the inverter circuit, the power device is worn out (deteriorated) through repeated use and will eventually be damaged. For this reason, for example, a device configured to monitor changes in the temperature of the power device and to estimate the product life of the power device or a device that realizes redundancy by using a plurality of inverter circuits have been proposed.